Cellular systems perform communications based on the cell unit. A cell is the geographic service area covered by a Base Station Transceiver Subsystem (BTS). In general, a cell is classified as an omni-cell or a three-sector cell. The sector represents the coverage angle of an antenna face, for example 120 degrees for a three-sector cell and 360 degrees for an omni-cell. A mobile station communicates with a base station that supports the cell within which the mobile station is located. The communication is performed via forward and reverse communication channels.
Certain cellular telecommunications networks have traditionally operated in the 824–849 MHz range, also known as the cellular hyperband. A more recent evolution in cellular telecommunications involves the adoption of the 1900 MHz hyperband for use in handling mobile and personal communications. The 1900 MHz hyperband is also known as the Personal Communication Services (PCS) hyperband. Standards that define cellular telephone operations in North America include the intersystem signaling standard IS-41 that is incorporated by reference herein.
Each of the frequency bands specified for the cellular and PCS hyperbands is allocated a plurality of voice or speech channels and at least one access or control channel. The control channel is used to control or supervise the operation of mobile stations by means of information transmitted to and received from the mobile stations. Such information may include, but is not limited to, incoming call signals, outgoing call signals, page signals, page response signals, location registration signals, voice channel assignments, maintenance instructions, short message service (SMS) messages, and cell selection or reselection instructions as mobile stations travel out of the radio coverage of one cell and into the radio coverage of another cell. The voice channel is used to carry subscriber telephonic communications as well as messages requesting mobile station assistance in making hand-off evaluations. The control and voice channels may operate in either an analog mode or a digital mode.
Many wireless service providers are beginning to supplement their existing RF spectrum with additional spectrum purchased from the other hyperband in order to increase network capacity. Legacy cell equipment is designed to support only a single hyperband. New systems simultaneously supporting both current wireless hyperbands (Cellular and PCS) are being designed. This presents the problem of supporting both hyperbands in the same cell, without completely altering the existing infrastructure designed to support cells of a single hyperband. In addition, future spectrum is planned for auction, thus further compounding the problem. Accordingly, the proposed solution should be easily expandable to support additional hyperbands.
Existing cellular telephone networks may have to simultaneously support radio telecommunications on multiple frequency bands. One solution is to have a mobile switching center (MSC) control transmission and reception equipment at one or more geographically coincident base stations to operate one cell in the cellular hyperband and another cell in PCS hyperband. In addition, adjacent exchanges, controlled by different MSCs, may have cells that operate in the cellular hyperband or cells operating in both the cellular and PCS hyperbands. However, the cells serving the cellular hyperband and the cells serving the PCS hyperband, although possibly covering the same area, are typically treated as independent cells. This solution has the disadvantage of artificially increasing the number of cells that must be supported by the wireless infrastructure, and the coordination of handoffs from one sector to another, as a mobile moves from one reception area to another, becomes a more complicated function.
It would be a distinct advantage to have a solution for supporting multiple hyperbands that is easily expandable to support additional hyperbands. It is an object of the present invention to provide such a solution.